1. Field of the Invention
The present invention relates to repair materials for concrete, and more particularly, to improved concrete repair materials containing fine aggregates, cement, and special chemical additives.
2. Related Art
Concrete structures and surfaces often develop cracks from environmental stresses, load stresses, and shrinkage during curing. For functional and/or aesthetic reasons, it is often desirable to repair these cracks. However, current repair systems are often considered temporary and suffer from problems including thermal incompatibility with the parent concrete, and re-cracking. More specifically, conventional thin concrete repair materials and systems are generally polymer-based or cementitious materials-based. Unfortunately, many of these systems fail after only a few years of service. Polymer-based systems do not generally perform well in an outdoor environment because of the thermal incompatibility of such systems with concrete, and frequently de-bond after a few years of exposure. Many cementitious systems have also been examined and have been found to not perform adequately. In this regard, many repairs using these materials crack or become de-bonded after exposure to actual field conditions, or deteriorate from other environmental causes, thereby leading to premature failure of the repair.
Another problem that must be faced in repairing thin surface defects in concrete structures is the effect of alkali aggregate reaction. This reaction causes a form of deterioration in the concrete structure resulting from a reaction between some types of cement and certain aggregates.